In recent years, there has been an increasing demand for “smart” personal care appliances that are capable of performing functionalities by detecting a number of physical parameters associated with a user. For example, the use of personal care appliances, such as toothbrushes, hair clippers, beard trimmers, hairdryers, etc. can be improved by changing the function of the appliance depending on the relative orientation and/or position of the appliance to the user.
Several methods have been described for determining the orientation of an appliance relative to a user, in particular a body part of a user (e.g. head). For example, in some conventional arrangements, the intensity and/or temperature of the airflow from a hairdryer can be adjusted according to the distance and/or angle of the airflow relative to a user's head.
There are a number of conventional methods for determining a relative orientation and/or position of a device to a user, and modifying the functionality of the device in some way depending on the determined orientation and/or position. For example, some conventional personal care appliances comprise an electromagnetic field sensor that is used in conjunction with a user head tracking device that comprises another electromagnetic field sensor. In such systems, the data captured by the electromagnetic field sensors from both the personal care appliance and the user head tracking device are transmitted to an embedded computer system such that the position and rotation of the personal care appliance can be monitored.
In conventional systems, using an electromagnetic system to determine the relative orientation of the appliance and the user requires a large amount of sensing hardware and processing powers.